import java.util.ArrayList;
import java.util.Scanner;

public class StudentSystem {
    public static void main(String[] args) {
        ArrayList<Student1> list=new ArrayList<>();

        while (true) {
            System.out.println("-----------欢迎来到学生管理系统-----------");
            System.out.println("1：添加学生");
            System.out.println("2：删除学生");
            System.out.println("3：修改学生");
            System.out.println("4：查询学生");
            System.out.println("5：退出");
            System.out.println("请输入您的选择");

            Scanner sc=new Scanner(System.in);
            String choose=sc.next();

            switch (choose){
                case "1"->addStudent(list);
                case "2"-> deleteStudent(list);
                case "3"-> updateStudent(list);
                case "4"->
                    queryStudent(list);
                case "5"->{
                    System.out.println("退出");
                    System.exit(0);
                }
                default -> System.out.println("没有这个选项");
            }
        }
    }

    //添加学生
    public  static  void  addStudent(ArrayList<Student1> list){
        Student1 s=new Student1();
        Scanner sc=new Scanner(System.in);
        String id=null;

        while (true) {
            System.out.println("请输入学生id");
            id=sc.next();
            boolean flag=contains(list,id);
            if(flag){
                System.out.println("id已存在，请重新录入");
            }else {
                s.setId(id);
                break;
            }
        }

        System.out.println("请输入学生姓名");
        String name= sc.next();
        s.setName(name);

        System.out.println("请输入学生年龄");
        int age= sc.nextInt();
        s.setAge(age);

        System.out.println("请输入学生家庭住址");
        String address= sc.next();
        s.setAddress(address);

        list.add(s);
        System.out.println("学生信息添加成功");

    }

    //删除学生
    public  static  void  deleteStudent(ArrayList<Student1> list){
        Scanner sc=new Scanner(System.in);
        System.out.println("请输入要删除的id");
        String id=sc.next();
        int index=getIndex(list,id);
        if(index>=0){
            list.remove(index);
            System.out.println("id为"+id+"的学生信息删除成功");
        }else {
            System.out.println("id不存在，删除失败");
        }
    }

    //修改学生
    public  static  void  updateStudent(ArrayList<Student1> list){
        Scanner sc=new Scanner(System.in);
        System.out.println("请输入要修改学生的id");
        String id=sc.next();
        int index=getIndex(list,id);
        if(index==-1){
            System.out.println("要修改的id"+id+"不存在，请重新输入");
            return;
        }

        Student1 stu=list.get(index);

        System.out.println("请输入要修改学生姓名");
        String newName=sc.next();
        stu.setName(newName);

        System.out.println("请输入要修改学生年龄");
        int newAge=sc.nextInt();
        stu.setAge(newAge);

        System.out.println("请输入要修改学生家庭住址");
        String newAddress=sc.next();
        stu.setAddress(newAddress);

        System.out.println("学生信息修改成功");

    }

    //查询学生
    public  static  void  queryStudent(ArrayList<Student1> list){
        System.out.println("查询学生");

        if(list.size()==0){
            System.out.println("当前无学生信息，请稍后查询");
            return;
        }

        System.out.println("id\t\t姓名\t年龄\t家庭住址");
        for (int i = 0; i < list.size(); i++) {
            Student1 stu=list.get(i);
            System.out.println(stu.getId()+"\t"+stu.getName()+"\t"+stu.getAge()+"\t"+stu.getAddress());
        }
    }

    //判断id是否唯一（判断是否存在）
    public static boolean contains(ArrayList<Student1> list,String id){

       /* for (int i = 0; i < list.size(); i++) {
            Student1 stu=list.get(i);
            String id1=stu.getId();
            if(id1.equals(id)){
                return true;
            }
        }
        return false;*/

        return getIndex(list,id)>=0;//难点
    }

    //通过id获取索引
    public static int getIndex(ArrayList<Student1> list,String id){
        for (int i = 0; i < list.size(); i++) {
            Student1 stu=list.get(i);
            String id1=stu.getId();
            if(id1.equals(id)){
                return i;
            }
        }

        return -1;
    }

}
